/*

  * This file is part of dependency-check-core.

  *

  * Licensed under the Apache License, Version 2.0 (the "License");

  * you may not use this file except in compliance with the License.

  * You may obtain a copy of the License at

  *

  *     http://www.apache.org/licenses/LICENSE-2.0

  *

  * Unless required by applicable law or agreed to in writing, software

  * distributed under the License is distributed on an "AS IS" BASIS,

  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

  * See the License for the specific language governing permissions and

  * limitations under the License.

  *

  * Copyright (c) 2012 Jeremy Long. All Rights Reserved.

  */

 package org.owasp.dependencycheck.data.lucene;

 import java.io.Reader;

 import org.apache.lucene.analysis.Analyzer;

 import org.apache.lucene.analysis.TokenStream;

 import org.apache.lucene.analysis.Tokenizer;

 import org.apache.lucene.analysis.core.LowerCaseFilter;

 import org.apache.lucene.analysis.core.StopAnalyzer;

 import org.apache.lucene.analysis.core.StopFilter;

 import org.apache.lucene.analysis.miscellaneous.WordDelimiterFilter;

 import org.apache.lucene.util.Version;

 /**

  * A Lucene field analyzer used to analyzer queries against the CPE data.

  *

  * @author Jeremy Long <jeremy.long@owasp.org>

  */

 public class SearchFieldAnalyzer extends Analyzer {

     /**

      * The Lucene Version used.

      */

     private final Version version;

     /**

      * A local reference to the TokenPairConcatenatingFilter so that we can clear any left over state if this analyzer

      * is re-used.

      */

     private TokenPairConcatenatingFilter concatenatingFilter;

     /**

      * Constructs a new SearchFieldAnalyzer.

      *

      * @param version the Lucene version

      */

     public SearchFieldAnalyzer(Version version) {

         this.version = version;

     }

     /**

      * Creates a the TokenStreamComponents used to analyze the stream.

      *

      * @param fieldName the field that this lucene analyzer will process

      * @param reader a reader containing the tokens

      * @return the token stream filter chain

      */

     @Override

     protected TokenStreamComponents createComponents(String fieldName, Reader reader) {

         final Tokenizer source = new AlphaNumericTokenizer(version, reader);

         TokenStream stream = source;

         stream = new WordDelimiterFilter(stream,

                 WordDelimiterFilter.GENERATE_WORD_PARTS

                 | WordDelimiterFilter.GENERATE_NUMBER_PARTS

                 | WordDelimiterFilter.PRESERVE_ORIGINAL

                 | WordDelimiterFilter.SPLIT_ON_CASE_CHANGE

                 | WordDelimiterFilter.SPLIT_ON_NUMERICS

                 | WordDelimiterFilter.STEM_ENGLISH_POSSESSIVE, null);

         stream = new LowerCaseFilter(version, stream);

         stream = new UrlTokenizingFilter(stream);

         concatenatingFilter = new TokenPairConcatenatingFilter(stream);

         stream = concatenatingFilter;

         stream = new StopFilter(version, stream, StopAnalyzer.ENGLISH_STOP_WORDS_SET);

         return new TokenStreamComponents(source, stream);

     }

     /**

      * <p>

      * Resets the analyzer and clears any internal state data that may have been left-over from previous uses of the

      * analyzer.</p>

      * <p>

      * <b>If this analyzer is re-used this method must be called between uses.</b></p>

      */

     public void clear() {

         if (concatenatingFilter != null) {

             concatenatingFilter.clear();

         }

     }

 }